Stereoselective synthesis and characterization of novel trans-4-(thiophenyl)pyrazolyl-β-lactams and their C–3 functionalization
作者:Preety Saini、S.S. Bari、Subash C. Sahoo、Sadhika Khullar、Sanjay K. Mandal、Aman Bhalla
DOI:10.1016/j.tet.2019.07.001
日期:2019.8
A stereoselective synthesis and C–3 functionalization of a long series of novel hybrid 4-(thiophenyl)pyrazolyl-β-lactams have been carried out. The divergent substrate scope and mechanistic insights were examined to delineate the generality of reaction that favored trans-β-lactams 4a-q almost exclusively in all cases. The C–3 functionalization was achieved by Lewis acid assisted nucleophilic substitution
进行了一系列新型杂合4-(硫代苯基)吡唑基-β-内酰胺类化合物的立体选择性合成和C-3功能化。研究了不同的底物范围和机理的见解,以描绘出几乎在所有情况下都倾向于反式-β-内酰胺4a-q的反应的一般性。的C-3官能化通过路易斯酸辅助亲核取代反应来实现顺-3-氯β内酰胺6A-E ,得到顺式-3-单取代-β内酰胺器7a-e 。β-内酰胺7a-e的顺式立体化学在代表性的情况下(7a,b)通过用阮内镍进行立体定向脱硫进一步建立了α-内酰胺基,从而形成顺式-β-内酰胺8a,b。使用FT-IR,1D NMR(1 H和13 C),2D NMR(1 H– 1 H COSY,1 H– 13 C HSQC和13 C DEPT– 135),代表性分析(4b,e)中的元素分析(CHN),质谱(ESI-MS)和单晶X射线晶体学。该顺和反式 相对于β-内酰胺环的C4-H,确定了C-3处氢/氯/亲核取代基的构型。